AN INTERNAL FRICTION STUDY OF N-H AND O-H PAIRS IN SINGLE CRYSTAL OF NIOBIUM AT LOW TEMPERATURES R. Hanada, M. Shinohara, Y. Sado and H. Kimura J. Phys. Colloques, 42 C5 (1981) C5-757-C5-761 DOI: 10.1051/jphyscol:19815117